1. Technical Field
The present invention relates generally to optical networks. More particularly, the present invention relates to transmission bypass techniques in fiber optic networks.
2. Description of the Related Art
Fiber optic networks are used in a variety of applications. In some applications, such as signal routing in a device interconnection network, devices connected to the fiber optic network are interconnected in series such that the output from each device is connected to the input of another device, such that the fiber optic network forms a loop network. However, a problem arises in such networks when one of the devices connected to the network is not powered on or fails. This essentially breaks the loop or chain network and prevents the network devices on either side of the powered-down device from communicating. It would be desirable to provide a network device that allows fiber optic transmission even when not powered.
An optical transmission bypass device attaching a network device to a fiber optic network allows fiber optic transmissions to bypass the network device when not powered, thereby maintaining continuity of the fiber network. The optical transmission bypass device comprises a first and second optical port, a first and second actuating optical reflector and an optical transmission line. The first optical port is optically coupled to a first optical transmission line, and the second optical port is optically coupled to a second optical transmission line. The first actuating optical reflector has a reflective face that, in a first state, is disposed to place the reflective face of the first actuating optical reflector in a first position with respect to an optical path of the first optical port, and, in a second state, is disposed to place the reflective face of the first actuating optical reflector in a second position with respect to the optical path of the first optical port, wherein the first actuating optical reflector is in the first state when the first actuating optical reflector is not electrically powered. The second actuating optical reflector has a reflective face that, in the first state, is disposed to place the reflective face of the second actuating optical reflector in a first position with respect to an optical path of the second optical port, and, in the second state, is disposed to place the reflective face of the second actuating optical reflector in a second position with respect to the optical path of the second optical port, wherein the second actuating reflector is in the first state when the second actuating optical reflector is not electrically powered. The optical transmission line is positioned between the first actuating reflector and the second actuating reflector, wherein, in the first state: the optical transmission line is optically coupled at a first end to the first optical port by the reflective face of the first actuating optical reflector and optically coupled at a second end to the second optical port by the reflective face of the second actuating optical reflector, such that received optical transmission data at the first optical port is reflected from the first reflective face of the first actuating optical reflector into the first end of the optical transmission line and out of the second end of the optical transmission line and reflected from the second reflective face of the second actuating optical reflector to the second optical port to provide the received optical transmission data for transmission by the second optical transmission line. In the second state, the optical transmission line is not optically coupled at a first end to the first optical port by the reflective face of the first actuating optical reflector and not optically coupled at a second end to the second optical port by the reflective face of the second actuating optical reflector.
In an alternative embodiment, in the second state, the reflective face of the first actuating optical reflector in the second position with respect to the optical path of the received optical transmission data is positioned such that the reflective face of the first actuating optical reflector is outside the optical path of the received optical transmission data, allowing the received optical transmission data at the first optical port to pass directly to a receiver, and the reflective face of the second actuating optical reflector in the second position with respect to the optical path of the optical transmission data provided by the second optical port to the second optical transmission line is positioned such that the reflective face of the second actuating optical reflector is outside the optical path of the optical transmission data provided by the second optical port, allowing optical transmission data from a transmitter to pass directly to the second optical port.
The above as well as additional objectives, features, and advantages of the present invention will become apparent in the following detailed written description.